/*
 *
 * Copyright (c) 2006-2011 Sam Collett (http://www.texotela.co.uk)
 * Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
 * and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
 * 
 * Version 1.3
 * Demo: http://www.texotela.co.uk/code/jquery/numeric/
 *
 */
(function($) {
    /*
 * Allows only valid characters to be entered into input boxes.
 * Note: fixes value when pasting via Ctrl+V, but not when using the mouse to paste
  *      side-effect: Ctrl+A does not work, though you can still use the mouse to select (or double-click to select all)
 *
 * @name     numeric
 * @param    config      { decimal : "." , negative : true }
 * @param    callback     A function that runs if the number is not valid (fires onblur)
 * @author   Sam Collett (http://www.texotela.co.uk)
 * @example  $(".numeric").numeric();
 * @example  $(".numeric").numeric(","); // use , as separater
 * @example  $(".numeric").numeric({ decimal : "," }); // use , as separator
 * @example  $(".numeric").numeric({ negative : false }); // do not allow negative values
 * @example  $(".numeric").numeric(null, callback); // use default values, pass on the 'callback' function
 *
 */
    $.fn.numeric = function(config, callback)
    {
        if(typeof config === 'boolean')
        {
            config = {
                decimal: config
            };
        }
        config = config || {};
        // if config.negative undefined, set to true (default is to allow negative numbers)
        if(typeof config.negative == "undefined") config.negative = true;
        // set decimal point
        var decimal = (config.decimal === false) ? "" : config.decimal || ".";
        // allow negatives
        var negative = (config.negative === true) ? true : false;
        // callback function
        var callback = typeof callback == "function" ? callback : function(){};
        // set data and methods
        return this.data("numeric.decimal", decimal).data("numeric.negative", negative).data("numeric.callback", callback).keypress($.fn.numeric.keypress).keyup($.fn.numeric.keyup).blur($.fn.numeric.blur);
    };

    $.fn.numeric.keypress = function(e)
    {
        // get decimal character and determine if negatives are allowed
        var decimal = $.data(this, "numeric.decimal");
        var negative = $.data(this, "numeric.negative");
        // get the key that was pressed
        var key = e.charCode ? e.charCode : e.keyCode ? e.keyCode : 0;
        // allow enter/return key (only when in an input box)
        if(key == 13 && this.nodeName.toLowerCase() == "input")
        {
            return true;
        }
        else if(key == 13)
        {
            return false;
        }
        var allow = false;
        // allow Ctrl+A
        if((e.ctrlKey && key == 97 /* firefox */) || (e.ctrlKey && key == 65) /* opera */) return true;
        // allow Ctrl+X (cut)
        if((e.ctrlKey && key == 120 /* firefox */) || (e.ctrlKey && key == 88) /* opera */) return true;
        // allow Ctrl+C (copy)
        if((e.ctrlKey && key == 99 /* firefox */) || (e.ctrlKey && key == 67) /* opera */) return true;
        // allow Ctrl+Z (undo)
        if((e.ctrlKey && key == 122 /* firefox */) || (e.ctrlKey && key == 90) /* opera */) return true;
        // allow or deny Ctrl+V (paste), Shift+Ins
        if((e.ctrlKey && key == 118 /* firefox */) || (e.ctrlKey && key == 86) /* opera */
            || (e.shiftKey && key == 45)) return true;
        // if a number was not pressed
        if(key < 48 || key > 57)
        {
            /* '-' only allowed at start and if negative numbers allowed */
            if(this.value.indexOf("-") != 0 && negative && key == 45 && (this.value.length == 0 || ($.fn.getSelectionStart(this)) == 0)) return true;
            /* only one decimal separator allowed */
            if(decimal && key == decimal.charCodeAt(0) && this.value.indexOf(decimal) != -1)
            {
                allow = false;
            }
            // check for other keys that have special purposes
            if(
                key != 8 /* backspace */ &&
                key != 9 /* tab */ &&
                key != 13 /* enter */ &&
                key != 35 /* end */ &&
                key != 36 /* home */ &&
                key != 37 /* left */ &&
                key != 39 /* right */ &&
                key != 46 /* del */
                )
                {
                allow = false;
            }
            else
            {
                // for detecting special keys (listed above)
                // IE does not support 'charCode' and ignores them in keypress anyway
                if(typeof e.charCode != "undefined")
                {
                    // special keys have 'keyCode' and 'which' the same (e.g. backspace)
                    if(e.keyCode == e.which && e.which != 0)
                    {
                        allow = true;
                        // . and delete share the same code, don't allow . (will be set to true later if it is the decimal point)
                        if(e.which == 46) allow = false;
                    }
                    // or keyCode != 0 and 'charCode'/'which' = 0
                    else if(e.keyCode != 0 && e.charCode == 0 && e.which == 0)
                    {
                        allow = true;
                    }
                }
            }
            // if key pressed is the decimal and it is not already in the field
            if(decimal && key == decimal.charCodeAt(0))
            {
                if(this.value.indexOf(decimal) == -1)
                {
                    allow = true;
                }
                else
                {
                    allow = false;
                }
            }
        }
        else
        {
            allow = true;
        }
        return allow;
    };

    $.fn.numeric.keyup = function(e)
    {
        var val = this.value;
        if(val.length > 0)
        {
            // get carat (cursor) position
            var carat = $.fn.getSelectionStart(this);
            // get decimal character and determine if negatives are allowed
            var decimal = $.data(this, "numeric.decimal");
            var negative = $.data(this, "numeric.negative");
		
            // prepend a 0 if necessary
            if(decimal != "")
            {
                // find decimal point
                var dot = val.indexOf(decimal);
                // if dot at start, add 0 before
                if(dot == 0)
                {
                    this.value = "0" + val;
                }
                // if dot at position 1, check if there is a - symbol before it
                if(dot == 1 && val.charAt(0) == "-")
                {
                    this.value = "-0" + val.substring(1);
                }
                val = this.value;
            }
		
            // if pasted in, only allow the following characters
            var validChars = [0,1,2,3,4,5,6,7,8,9,'-',decimal];
            // get length of the value (to loop through)
            var length = val.length;
            // loop backwards (to prevent going out of bounds)
            for(var i = length - 1; i >= 0; i--)
            {
                var ch = val.charAt(i);
                // remove '-' if it is in the wrong place
                if(i != 0 && ch == "-")
                {
                    val = val.substring(0, i) + val.substring(i + 1);
                }
                // remove character if it is at the start, a '-' and negatives aren't allowed
                else if(i == 0 && !negative && ch == "-")
                {
                    val = val.substring(1);
                }
                var validChar = false;
                // loop through validChars
                for(var j = 0; j < validChars.length; j++)
                {
                    // if it is valid, break out the loop
                    if(ch == validChars[j])
                    {
                        validChar = true;
                        break;
                    }
                }
                // if not a valid character, or a space, remove
                if(!validChar || ch == " ")
                {
                    val = val.substring(0, i) + val.substring(i + 1);
                }
            }
            // remove extra decimal characters
            var firstDecimal = val.indexOf(decimal);
            if(firstDecimal > 0)
            {
                for(var i = length - 1; i > firstDecimal; i--)
                {
                    var ch = val.charAt(i);
                    // remove decimal character
                    if(ch == decimal)
                    {
                        val = val.substring(0, i) + val.substring(i + 1);
                    }
                }
            }
            // set the value and prevent the cursor moving to the end
            this.value = val;
            $.fn.setSelection(this, carat);
        }
    };

    $.fn.numeric.blur = function()
    {
        var decimal = $.data(this, "numeric.decimal");
        var callback = $.data(this, "numeric.callback");
        var val = this.value;
        if(val != "")
        {
            var re = new RegExp("^\\d+$|\\d*" + decimal + "\\d+");
            if(!re.exec(val))
            {
                callback.apply(this);
            }
        }
    };

    $.fn.removeNumeric = function()
    {
        return this.data("numeric.decimal", null).data("numeric.negative", null).data("numeric.callback", null).unbind("keypress", $.fn.numeric.keypress).unbind("blur", $.fn.numeric.blur);
    };

    // Based on code from http://javascript.nwbox.com/cursor_position/ (Diego Perini <dperini@nwbox.com>)
    $.fn.getSelectionStart = function(o)
    {
        if (o.createTextRange)
        {
            var r = document.selection.createRange().duplicate();
            r.moveEnd('character', o.value.length);
            if (r.text == '') return o.value.length;
            return o.value.lastIndexOf(r.text);
        } else return o.selectionStart;
    };

    // set the selection, o is the object (input), p is the position ([start, end] or just start)
    $.fn.setSelection = function(o, p)
    {
        // if p is number, start and end are the same
        if(typeof p == "number") p = [p, p];
        // only set if p is an array of length 2
        if(p && p.constructor == Array && p.length == 2)
        {
            if (o.createTextRange)
            {
                var r = o.createTextRange();
                r.collapse(true);
                r.moveStart('character', p[0]);
                r.moveEnd('character', p[1]);
                r.select();
            }
            else if(o.setSelectionRange)
            {
                o.focus();
                o.setSelectionRange(p[0], p[1]);
            }
        }
    };

})(jQuery);